Yes, of course, you can, and in fact, many people especially in the beginning rank their sites without backlinks, as backlinks aren't something that you will insert as soon as you create a site as they require some time and proof of traffic volume. So, in the first phase, you should focus mainly on adding quality keywords to your content and try to rank your site high with them. Do thorough research to find keywords that have a lot of search volume and that aren't so competitive at the same time, make a list, and start adding them on different pages on the site. For this purpose, creating some good blog sections on the site would be useful as well.